The present invention relates to catalytic converters and more particularly relates to weldless flanged catalytic converters and a method for preparing the same.
It is known in the art relating to catalytic converters to connect the catalytic converter at its inlet end to an exhaust pipe, such as from an internal combustion engine, by means of a fixed flange that is welded to the catalytic converter. The welded flange on the catalytic converter inlet end is secured to a similar flange on the exhaust pipe to form a gas tight seal. FIG. 1 shows a cross-sectional fragmentary view of a typical prior art method for connecting a catalytic converter to an exhaust pipe. The catalytic converter shell 10 comprises a body portion 12 (often tubular) having an exhaust gas inlet 14. The body portion 12 tapers at the inlet 14 to form a truncated cone-shaped front portion 16. Connected to the converging end of the cone-shaped front portion 16 is a pipe piece 18 (xe2x80x9csnorkel tubexe2x80x9d). Alternately, the snorkel tube is formed as a part of the converter shell. A catalytic element of a honeycomb structure is disposed within the converter body and insulated and supported therein by a layer of cushion material (element and cushion or mat not shown). A flange member 20 is fixedly secured to the outer surface of the snorkel tube 18 by welding. The exhaust pipe 22 of an internal combustion engine provides a conduit for exhaust gas emitted from the combustion chambers in the engine to the converter inlet 14. The exhaust pipe 22 has on one end a flange member 24 secured to the outer surface of the exhaust pipe 22 by welding. A gasket 26 is normally placed between flanges 20 and 24 to form a gas tight seal. The exhaust pipe flange member 24 is connected to the flange member 20 on the converter snorkel tube 18 by any suitable means, such as with bolts 28 and nuts 30.
Catalytic converters may be connected to exhaust pipes and tailpipes by means of the above-described welded flanges. However, the use of such welded flanges causes the catalytic converter system to have an increased number of parts adding to the overall complexity and weight of the system. Further, use of welded flanges on the outlet and inlet snorkel tubes of the converter adds considerable expense to the manufacturing process and complexity to the assembly process. Further, the welding and machining required with such welded flanges has adverse quality implications such as warping of the converter metal, the possibility of weld imperfections, etc.
What is needed in the art is an improved catalytic converter and method for preparing the same. What is further needed in the art is an improved catalytic converter-exhaust pipe connection system. What is further needed is a catalytic converter connection system having a simplified design over currently available systems. What is further needed in the art is a catalytic converter connection system that can be produced at reduced cost and of improved quality over currently available designs.
A weldless flanged catalytic converter comprises a body having an exhaust inlet end and an outlet end and a snorkel tube disposed at one or both of the ends, the snorkel tube having a first end and a second end. The first end of the snorkel tube extends from the converter body. The second, distal end of at least one of the snorkel tubes comprises a weldless flange integrally formed from the snorkel. A movable flange is disposed about the snorkel tube between the first and second ends of the snorkel tube. In a preferred embodiment, the movable flange is disposed about the snorkel tube prior to the formation of the weldless flange.
The present weldless flanged catalytic converter provides a connection system such as to the mating flange on an exhaust pipe or a tailpipe.
The present method for preparing a weldless flanged catalytic converter comprises disposing a movable flange about the snorkel tube of the catalytic converter and forming a weldless flange from a portion of the second end of the snorkel tube. The forming may comprise any suitable technique such as drawing, rolling, forging, upsetting, or other metal forming technique.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.